Climate Change An Ice Age Proves the Greenhouse Effect
For a long time, the ice age thought to have taken place over 443 million years ago late in the Ordovician period (460 to 440 million years ago) was a riddle for geologists. After all, it came, so scientists thought, during a time of intense volcanic activity around the globe with frequent eruptions spewing millions of tons of carbon dioxide into the atmosphere. Instead of a cold, frozen earth, the greenhouse gases emitted by the world's erupting mountains should have created a warming effect. If instead the result was an ice age, then current theories on climate change and global warming would have been seriously questionable.
Indeed, the seeming conflict has for years provided some climate experts with valid arguments against the theory of global warming -- doubts that a number of world governments, most notably the United States, have relied on as justification for doing absolutely nothing to address the dangers of climate change.
"How can you have ice when CO2 levels are through the roof?" asked Ohio State University geologist Matthew Saltzman. "That was the dilemma that we were faced with."
Now, however, Saltzman may have found a solution to the dilemma. He has found concrete indications that the ice age in question likely took place fully 10 million years earlier than scientists had assumed -- 453 million years ago -- thus avoiding the conflict. It only ended, he thinks, as a result of the greenhouse effect -- which saw CO2 levels as much as 20 times higher than today -- set off by the world's volcanoes at the end of the Ordovician.
Saltzman examined large deposits of quartz sand in three locations worldwide -- in the US state of Nevada (then located on the ocean coast) and in Norway and Estonia -- that were formed during the mid to late Ordovician period. Saltzman suspects that the sands were formed when the water levels fell low enough to expose quartz rock to the elements, thus creating erosion that formed the sand.
Saltzman believes that, because the same phenomenon took place in three locations far away from each other, the rocks became exposed to the elements through a global event rather than due to local circumstances. An ice age, which freezes huge quantities of water, could have caused a lowering of the ocean levels thus exposing the rocks.
"If sea level is dropping globally at the same time, it can't be a local tectonic feature," Saltzman said. "It's got to be the result of global ice buildup."
The geologist also analyzed limestone sediments from the sites and found that there were large amounts of organic carbon present in the oceans at the same time -- a finding which leads to the conclusion that there was then relatively little CO2 in the atmosphere. This conclusion fits perfectly with the conditions that prevail during an ice age.
"Our results are consistent with the notion that CO2 concentrations drive climate," said Saltzman. "I think we now have good evidence that resolves this mismatch," between the ice age and the age of a multitude of volcanic eruptions.
Saltzman is planning to bolster his results through an examination of sites in Russia and in parts of South America and North Africa that would have been covered in ice during this period. He is hoping to find more evidence of a drop in sea level at the time.
